Tom K. answered 07/18/20
Knowledgeable and Friendly Math and Statistics Tutor
The standard notation for the normal distribution is N(mean, variance)
The variance of the sample of size n is the variance of the population/n
The sample mean equals the population mean.
Q1: N(42, 10/81)
Q2: N(42, 10/16) on N(42, 5/8)
Q3: this question can be interpreted in so many ways; one way is that the confidence interval can be one-sided or two-sided - of course, the one-sided can be either way.
Q4: The probability that the sample mean is > 20.26 is .8084.
There is really no way to interpret beyond restating this.
Q5; Z ~ (0, 1). P(z > 0) = 1/2
Tom K.
No. This is because the notation N(42,10) refers to the mean and variance, not the mean and standard deviation. If your course is using non-standard notation, your answer would be correct.07/18/20
Tom K.
I left off the N. Z ~ N(0, 1)07/18/20